RU2347990C1 - Installation for drying and heat treatment of catalysts - Google Patents

Abstract

FIELD: heating; drying.

SUBSTANCE: present invention pertains to the method of drying solutions, obtaining a granular product with high hygroscopicity, and can be used in different fields of chemical engineering and related industries, where there are high demands for value of final water content in the product. The installation for drying and heat treatment of catalysts has a plunger pump for supplying the initial solution, a filter for separating impurities, a spray-type drier, designed for drying and granulating a catalyst from the solution, battery cyclones for trapping the end product and directing it to an auger-type or belt-type conveyer for the dried product. The installation also has a ventilator, smoke exhaust and a heat generator. Through the smoke exhaust, the recycle stream is directed into a Venturi scrubber for collection in a container in the bunker part of the scrubber in form of a deposit and from the drop catcher. The solution is moved into the scrubber by the pump. The drying agent is moved into the heat treatment device by the ventilator through the heat generator. The separator moves the dried product to the cyclone of a pressure feed. The heat treatment device is designed for creating a two-stage temperature mode for heat treatment and regulates the time spent by the catalyst in each stage: in the first stage the drying agent is put into the top part of the device, and the vapour-gas medium, in contact with catalyst particles, is put into the bottom part of the device. The end product goes into a cooler. The scrubber with drop catcher is designed for the final process of dust collection of the recycle stream and cleaning the drying agent discharged into the atmosphere. The installation has a system of cleaning exhaust drying agent, a unit for cooling the end product, a batched feed unit, means of transporting the product inside the installation, a bin for collecting the end product and other units, creating the necessary infrastructure of the complex installation. The system for feeding in the moist initial solution is in form of acoustic burners, with a case in which there is an acoustic generator, comprising a resonator, and inlet pipes of atomising agent and solution. The case is in form of a cup with a bottom, inside of which there is a case for the acoustic generator, which is in form of a hollow rod with a V-shaped aperture and a nozzle. The solution enters the annular clearance between the outer surface of the resonator and the inner surface of the nozzle. The inlet channel of the solution is at a tangent to the inner surface of the cup and is in form of a rectangular aperture. Air is let in through a connecting pipe in the case, a valve, located over the saddle of the resonator, and the opening of the resonator, and then goes through at least, one V-shaped aperture, which is at an angle of 30°-60° to the axis of the resonator. In the annular clearance between the inner surface of the cup and the outer surface of the resonator, there is a helical guide, capable of creating a swirling stream of solution, getting into the channel.

EFFECT: increased efficiency of drying and heat treatment processes.

2 cl, 2 dwg

Description

The invention relates to a method for drying solutions to obtain a granular product with increased hygroscopicity, and can be used in various fields of chemical technology and related industries, where there are increased requirements for the final moisture content of the product.

Closest to the claimed object is a method for producing granular calcium chloride anhydrous by feeding into the drum a powdery fraction of the product (fine fraction + powder after crushing), partially dehydrated product and solution (RF patent No. 2093766, F26B 3/12 prototype).

The disadvantages of this method include, first of all, the difficulty of controlling the process in the presence of three product streams with different humidity: anhydrous powder, partially dehydrated lumpy product and solution. This leads to the formation of both small and large-sized product, which, in turn, reduces the yield of product fraction and increases the load on the crushing and screening equipment.

The disadvantages of the device for granulating CaCl ₂ are significant capex, difficulties in controlling the process due to the large number of input streams and low reliability of the process due to significant deposits in the drum.

The technical result is an increase in the efficiency of drying and calcining processes.

This is achieved by the fact that in the installation for drying and calcining the catalyst, containing a plunger pump for supplying the initial solution, an impurity separation filter, a spray dryer designed for drying and granulating the catalyst from the solution, battery cyclones for capturing the finished product and sending it to the screw or belt the conveyor of the dried product, according to the invention, additionally contains a fan, a smoke exhaust and a heat generator, while the smoke exhaust is guided by the retur stream into a Venturi scrubber to collect it a tank from the hopper part of the scrubber as sludge and from a droplet eliminator, and the pump feeds the solution into the scrubber, while the fan feeds the drying agent into the calcining apparatus through the heat generator, and the separator delivers the dried product to the pneumatic conveying cyclone, and the calcining apparatus is designed to create a two-stage temperature calcination mode and providing a regulated catalyst residence time in each stage: the first stage is provided by supply of drying agent This is to the upper part of the apparatus, and the vapor-gas medium in contact with the catalyst particles is fed to the lower part of the apparatus, the finished product enters the product cooler, while the scrubber with a droplet eliminator is intended for the final process of dust retention and cleaning of the drying agent leaving the atmosphere, while installing equipped with a system for cleaning the spent drying agent, a cooling unit for the finished product, a metering unit, transport of the product inside the unit, a bin for the finished product other nodes creating the necessary infrastructure for the complete installation, while the wet feed solution supply system is made in the form of acoustic nozzles containing a housing with an acoustic oscillation generator containing a resonator located inside and tubes for supplying a spraying agent and solution, the housing being made in the form of a glass with the bottom, with the acoustic oscillation generator located inside the housing in the form of a hollow rod with a wedge gap and a nozzle, while the solution enters the annular gap, made between the outer surface of the resonator and the inner surface of the nozzle, and the channel for supplying the solution is located tangentially to the inner surface of the glass and is made in the form of a rectangular slit, while air is supplied through a fitting in the housing, an air supply valve located above the resonator seat, and a cavity of the resonator and then enters at least one wedge slot located at an angle of 30 ° -60 ° relative to the axis of the resonator, and in the annular gap between the inner surface of the glass and the outer surface A helical guiding device is placed on the resonator side, which contributes to the creation of a vortex flow of the solution entering the channel.

Figure 1 presents a diagram of the proposed installation for drying and calcining a microspherical cracking catalyst, figure 2 is a diagram of a pneumatic acoustic nozzle.

The apparatus for drying and calcining a microspherical cracking catalyst comprises a plunger pump 1 for supplying an initial solution, an impurity separation filter 2; spray dryer 3 with nozzles located in the upper part of the dryer for drying and granulating the catalyst from the solution, battery cyclones 4 for collecting the finished product and sending it to the screw or conveyor belt 16 of the dried product. By the smoke exhauster 5, the flow of reture (non-marketable trifles) is sent to the Venturi scrubber 6 to collect it into the tank 10 from the hopper part of the scrubber as sludge and from the drip trap 7. Pump 8 delivers the solution to the scrubber 6, and the drying agent is fed through the heat generator to the calcining agent apparatus 12. The separator 11 delivers the dried product into the cyclone 13 pneumatic transport. The heat generator is designed to produce a drying agent and has a fitting for supplying air and fuel and draining the drying agent into the dryer 3.

The acoustic nozzle (figure 2), contains a housing 27 made in the form of a glass with a bottom 28, with an acoustic oscillation generator located inside the housing in the form of a hollow rod-resonator 20 with a wedge slot 21 and a nozzle 16. The solution enters an annular gap made between the outer surface of the resonator 20 and the inner surface of the nozzle 16, and then into the annular gap 17 between the inner surface of the housing 27 and the outer surface of the cup 30. Then, through the channel 31 made in the side wall of the cup 30, mounted coaxially to the body 27, g the liquid enters the annular gap between the inner surface of the cup 30 and the outer surface of the resonator 20, and the channel 31 is located tangentially to the inner surface of the cup 30 and is made in the form of a rectangular slit.

Air is supplied through a nozzle 22 located coaxially with the nozzle body 27 through a tube 18 with an opening 23, an opening 25 made in the valve 24, located coaxially with the nozzle 22 and the hole 19 of the resonator 20, and then enters at least one wedge slot 21. The wedge gap 21 is located at an angle relative to the axis of the resonator 20, and the angle is in the optimal range of values: 30 ° ÷ 60 °. The valve 24 interacts with the seat 26, made in one piece with the resonator 20, and resting on an elastic gasket 29 located between the end surfaces of the cup 30 and the seat 26. In the annular gap between the inner surface of the cup 30 and the outer surface of the resonator 20 is placed a screw guide device 32 , contributing to the creation of a vortex flow of the solution entering the channel 31.

For the operation of the nozzle in optimal mode, the following ratios of its parameters are provided:

the ratio of the distance h ₂ from the outer surface of the bottom 28 of the housing 27 to the lower end of the valve 24 to the distance h from the outer surface of the bottom 28 of the housing 27 to the point of intersection of the axes of the inner hole 19 of the resonator 20 with the wedge gap 21 lies in the optimal range of values: h ₂ / h = 6 ÷ 10;

- the ratio of the distance h ₂ from the outer surface of the bottom 28 of the housing 27 to the lower end of the valve 24 to the distance h ₁ from the outer surface of the bottom 28 of the housing 27 to the axis of the channel 31 for supplying the solution lies in the optimal range of values: h ₂ / h ₁ = 1.5 ÷ 3;

- the ratio of the diameter d of the inner hole 19 of the resonator 20 to the diameter of the inner surface of the housing 27 lies in the optimal range of values: d / d ₄ = 0.1 ÷ 0.3;

- the ratio of the diameter d of the inner hole 19 of the resonator 20 to the diameter d _{1 of the} outer surface of the resonator 20 lies in the optimal range of values: d / d ₁ = 0.3 ÷ 0.7;

- the ratio of the diameter d _{2 of the} nozzle 16 to the diameter d _{1 of the} outer surface of the resonator 20 lies in the optimal range of values: d ₂ / d ₁ = 1.3 ÷ 1.7;

- the ratio of the diameter d _{2 of the} nozzle 16 to the distance h ₁ from the outer surface of the bottom 28 of the housing 27 to the axis of the channel 31 for supplying the solution lies in the optimal range of values: d ₂ / h ₁ = 3.5 ÷ 4.5;

- the ratio of the diameter d of the inner hole 19 of the resonator 20 to the distance h from the outer surface of the bottom 28 of the housing 27 to the point of intersection of the axes of the inner hole 19 of the resonator 20 with the wedge gap 21 lies in the optimal range of values: d / h = 0.3 ÷ 0.7.

The calcination apparatus 12 is designed to create a two-stage temperature regime of calcination and to provide a regulated residence time of the catalyst in each stage: the first stage is provided by the supply of a drying agent to the upper part of the apparatus, the vapor-gas medium in contact with the catalyst particles is supplied to the lower part of the apparatus, and the finished product enters the product cooler 14. A Venturi scrubber 15 with a droplet eliminator is designed for the final process of dust retention and cleaning of the effluent Yeru drying agent. The installation is equipped with a system for cleaning the spent drying agent, a cooling unit for the finished product, a metered-feed unit, product transport inside the unit, a finished product bin and other units that create the necessary infrastructure for the complete unit.

Installation for drying and calcining the catalyst operates as follows. The quality of the catalyst is finally formed in the calcining apparatus 12. The use of favorable physical and mechanical properties of the product microspheres, in particular, their high flowability, in the development of the column apparatus 12 with conductive heat transfer to the catalyst, made it possible to realize three necessary conditions for the quality of the process, which could not be done before in a column with a convective calcination mode:

- two-stage temperature mode;

- regulated catalyst residence time in each stage;

- vapor-gas medium in contact with the catalyst particles.

The acoustic nozzle for spraying liquids works as follows.

The spraying agent, for example air, is supplied through the opening 23 of the tube 18, then the hole 25 made in the valve 24 and the hole 19 of the resonator 20, after which it enters at least one wedge slot 21. The solution is through a channel 31 made in the side wall cup 30, enters the annular gap between the inner surface of the cup 30 and the outer surface of the resonator 20. As a result of the passage of the resonator 20 by a spraying agent (for example air), pressure pulsations occur in the latter, creating acoustic vibrations, the frequency of which depends on the parameters of the resonator. Acoustic vibrations of the spraying agent contribute to finer atomization of the solution supplied to the annular gap, while impacting, it creates sound vibrations affecting the stream of the solution. The specified nozzle provides good spray quality at low air flow rates. The experiments showed that at an air pressure of 100 kPa, the average droplet diameter is 90 μm, with an increase in air pressure by about 4 times (up to 400 kPa), the average droplet diameter decreases slightly and amounts to 87 μm.

Technical characteristics of the proposed installation: performance of the finished product - 500 kg / h; gas consumption - 1280 m ³ / h; installed power - 700 kW.

The installation is characterized by an energy-efficient process, due to the heat use of the spent heat carrier of the calcining furnace as a drying agent. One of the most effective catalysts in oil refining is the aluminosilicate microspherical catalyst. In the proposed installation, a new design of the spray drying chamber was developed: changing the gas distribution system with a local coolant supply to each nozzle, as well as replacing the dispersion method, created the conditions for obtaining an enlarged and more uniform grain composition with uniform heat treatment of dispersed particles in the dryer.

Claims (2)

1. Installation for drying and calcining the catalyst, comprising a plunger pump for supplying the initial solution, an impurity separation filter, a spray dryer for drying and granulating the catalyst from the solution, battery cyclones for collecting the finished product and sending it to the screw or belt conveyor of the dried product, characterized in that it contains a fan, a smoke exhaust and a heat generator, while the exhaust smoke is directed to the venturi scrubber to collect it into the tank from the hopper part of the scrubber sludge and from the droplet eliminator, and the pump feeds the solution into the scrubber, while the fan feeds the drying agent into the calcining apparatus through the heat generator, and the separator delivers the dried product to the pneumatic conveying cyclone, and the calcining apparatus is designed to create a two-stage calcination temperature regime and ensure a regulated time the stay of the catalyst in each stage: the first stage is provided by the supply of a drying agent to the upper part of the apparatus, and steam and gas the medium in contact with the catalyst particles is fed into the lower part of the apparatus, the finished product enters the product cooler, while the scrubber with a droplet eliminator is used for the final process of dust retention and cleaning of the drying agent leaving the atmosphere, and the unit is equipped with a system for cleaning the spent drying agent, unit cooling of the finished product, a metered-feed unit, product transport inside the unit, a finished product bin and other units that create the necessary and the infrastructure of the complete installation, while the wet feed solution supply system is made in the form of acoustic nozzles containing a housing with an acoustic oscillator located inside the resonator and tubes for supplying a spraying agent and solution, the housing being made in the form of a cup with a bottom placed inside the body of the generator of acoustic vibrations in the form of a hollow rod with a wedge gap and a nozzle, while the solution enters the annular gap made between the outer surface of the resonance ora and the inner surface of the nozzle, and the channel for supplying the solution is located tangentially to the inner surface of the glass and is made in the form of a rectangular slit, while air is supplied through a fitting in the housing, an air supply valve located above the resonator seat, and a cavity of the resonator, and then at least one wedge gap located at an angle of 30-60 ° relative to the axis of the resonator, and in the annular gap between the inner surface of the glass and the outer surface of the resonator there is a helical direction separating apparatus contributing to the creation of the vortex flow of the solution flowing through the channel. 2. Installation according to claim 1, characterized in that the ratio of the distance h ₂ from the outer surface of the bottom of the valve to the lower end of the valve to the distance h from the outer surface of the bottom of the valve to the point of intersection of the axes of the inner hole of the resonator with the wedge gap lies in the optimal range of values: h ₂ / h = 6 ÷ 10; the ratio of the distance h ₂ from the outer surface of the bottom of the body to the lower end of the valve to the distance h ₁ from the outer surface of the bottom of the body to the axis of the channel for supplying the solution lies in the optimal range of values: h ₂ / h ₁ = 1.5 ÷ 3; the ratio of the diameter d of the inner hole of the resonator to the diameter d _{4 of the} inner surface of the housing lies in the optimal range of values: d / d ₄ = 0.1 ÷ 0.3; the ratio of the diameter d of the inner hole of the resonator to the diameter d _{1 of the} outer surface of the resonator lies in the optimal range of values: d / d ₁ = 0.3 ÷ 0.7; the ratio of the diameter d _{2 of the} nozzle to the diameter d _{1 of the} outer surface of the resonator lies in the optimal range of values: d ₂ / d ₁ = 1.3 ÷ 1.7; the ratio of the diameter d _{2 of the} nozzle to the distance h ₁ from the outer surface of the bottom of the body to the axis of the solution supply channel lies in the optimal range of values: d ₂ / h ₁ = 3.5 ÷ 4.5, the ratio of the diameter d of the inner hole of the resonator to the distance h from the external the surface of the bottom of the body to the point of intersection of the axes of the inner hole of the resonator with the wedge gap lies in the optimal range of values: d / h = 0.3 ÷ 0.7.

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